Compositions containing sunscreen active agents are highly popular. Sunscreen active agents in such compositions protect keratinous material such as hair and skin from the harm caused by UV radiation, including harm from both UVA and UVB rays. A standard measure for determining the amount of protection a composition containing sunscreen active agent provides against UV radiation, particularly against UVB rays, is sun protection factor (SPF). However, given the finite amount of approved sunscreen active agents worldwide, increasing SPF of compositions containing sunscreen active agents can be difficult.
US patent application 2013/0129649 refers to a mixture of sunscreens which cannot be used in conjunction with oxides such as titanium dioxide and zinc oxide (namely avobenzone) and to specific ratios of specific sunscreen active agents. Other combinations of sunscreen active agents include those disclosed in U.S. Pat. No. 8,545,891, U.S. Pat. No. 8,557,227, U.S. Pat. No. 8,652,449, U.S. Pat. No. 8,691,192, U.S. Pat. No. 9,107,843, U.S. Pat. No. 9,132,074, U.S. Pat. No. 9,138,395, U.S. Pat. No. 9,138,396 and WO 2008042326.
Accordingly, one aspect of the present invention are compositions containing a combination of sunscreen active agents and having improved sun protection factor (SPF) properties. Other aspects of the present invention are methods of improving sun protection factor (SPF) properties of compositions containing sunscreen active agents and methods of preparing stable sunscreen compositions containing sunscreen active agents and metal oxides.